Miguel Lopez
Analyst · Cowen and Company
Thanks, Bruce. We had exceptional third quarter financial performance that exceeded our expectations. Please refer to our Investor Relations website for supplemental slides with graphs and tables summarizing our third quarter performance.
Total revenue of $231 million in the third quarter was comprised of $154 million for Cloud & Edge and $78 million for Packet and Optical. As Bruce mentioned, we continue to make great traction in our integration efforts. We plan to transition to providing business unit performance rather than legal entity financials, commencing in our fourth quarter of 2020. Given the ECI acquisition, all year-on-year comparisons are against Ribbon's standalone unless otherwise noted.
The third quarter 2020 GAAP financial results were as follows: total company revenue was $231 million; income per share was $0.04, which included a benefit of $0.03 from the release of a tax valuation allowance from our Ireland legal entity.
For Ribbon, as a total company, our non-GAAP third quarter performance was total revenue of $231 million versus $210 million last quarter and guidance range of $210 million to $220 million. Non-GAAP gross margin was 59%. Non-GAAP operating expenses were $98 million. Non-GAAP adjusted EBITDA was $43 million compared to $23 million last year and was above the guidance range of $25 million to $29 million. The improvement in adjusted EBITDA was due to both higher sales and better gross margins in both Cloud & Edge and Packet Optical Networks.
Non-GAAP diluted earnings per share was $0.16. Our diluted share count for the third quarter was 152 million shares compared to 111 million shares in the prior year, with the increase primarily driven by the ECI acquisition.
In the Cloud & Edge business, third quarter revenue was $154 million, reflecting growth of 12% from the previous year, driven by strong demand from our service providers. Our largest customer, Verizon, had some major projects this past quarter and accounted for 16% of our total revenue.
Software revenue grew significantly and was 69% of overall product sales in the quarter, resulting in better non-GAAP gross margins for Cloud & Edge of 66% versus 64% in the third quarter of the previous year. Our non-GAAP operating expenses of $63 million decreased 8% from the prior year period, driven by restructuring savings, temporary employee salary reductions and minimum travel and other discretionary expenses.
Cloud & Edge non-GAAP operating margin was 25%, which is 11 percentage points higher than last year. Non-GAAP adjusted EBITDA for Cloud & Edge was $42 million, which is $19 million higher than last year and reflects an exceptional adjusted EBITDA margin of 27%.
Now some additional perspective on Cloud & Edge. We recorded $75 million of product revenue and $79 million of services revenue. In the third quarter of 2020, Cloud & Edge software product revenue increased by $21 million or 39% compared to the same period last year. Software accounted for 69% of total product revenue in the third quarter compared to 51% in the third quarter of the previous year.
The Packet Optical Network business recorded third quarter revenue of $78 million, an increase of $14 million or 22% from the previous quarter. From a profitability perspective, we are pleased to report a positive adjusted EBITDA of $1 million for our ECI entity, driven by exceptionally strong gross margins of 46%, an increase of 700 basis points sequentially and continued expense controls.
We would like to provide some consolidated metrics for the third quarter. Our book to revenue ratio excluding maintenance, was 0.93x as compared to 1.12x in the second quarter of 2020. We continue to have a solid pipeline, providing us with good visibility into sales in the upcoming quarter.
Software revenue accounted for 43% of total product revenue across the company. Maintenance represented 32% of total revenue.
Our top 10 customers accounted for 49% of total revenues, which compares to 47% in the second quarter of 2020. Service providers accounted for 71% of revenue in the quarter and Enterprise customers represented 29%. International customers represented a greater percentage of revenue with 55% of revenue in the third quarter of 2020 as compared to 52% in the second quarter of 2020.
Turning to the balance sheet. We ended the quarter with cash and cash equivalents of $111 million, including restricted cash of $7 million. This is an increase of $17 million from the previous quarter. The principal balance of our term loan was $395 million as of September 30, which is down $2.2 million, reflecting a quarterly scheduled principal payment. Our revolver of $100 million remained undrawn. The effective interest rate on our term loan was 4.4% in the third quarter of 2020 as compared to 3.9% for the second quarter of 2020.
The rate increase was driven by the higher interest rate percentage for the $75 million tranche of our Term Loan B that was assigned on August 18. For details, please refer to our 8-K filed in August or in our 10-Q to be filed in the next business days.
Once again, we comfortably met our quarterly financial covenants. As per our credit facility calculations in Q3 2020, our leverage ratio was 2.6x versus a maximum of 4x, and our fixed charge coverage ratio of 3.9x versus a minimum of 1.25x.
From a cash perspective, the company generated $29 million of cash from operations which included an accelerated final payment receipt of $16.75 million from the Metaswitch legal settlement. We anticipate approximately $4 million for restructuring and acquisition-related expenses in the fourth quarter of 2020. Capital expenditures were $4 million for the quarter, which included $2 million of real estate leasehold improvements for our North Dallas offices facility.
Now let's turn the call back to Bruce.